Cartridge type check valve

ABSTRACT

A check valve comprises a housing defining a valve seat thereon and a valve member reciprocally mounted in the housing to normally engage the seat for blocking fluid flow therepast. Two pairs of split retaining members are mounted in axially spaced relationship on a stem of the valve member and are expanded axially thereon by a compression coil spring for biasing the valve member to its closed position. A stop member is secured on an end of the stem of the valve member to prevent movement of one pair of the retaining members therepast. A slot is formed axially through the stop member and extends partially in the stem of the valve member to expose an end of the spring.

BACKGROUND OF THE INVENTION

This invention relates to a check valve of the type having aspring-biased valve member reciprocally mounted therein to normallyblock fluid flow therepast and adapted to open when inlet pressuresexceed a predetermined maximum level. Such a check valve is normallyemployed in a hydraulic circuit of the type used for controlling theextension and retraction of a hydraulic cylinder employed forselectively moving a work tool on heavy construction machines.Manufacturing and servicing costs dictate the desirability of a checkvalve which can be precalibrated and assembled and disassembledexpeditiously for servicing or adjustment purposes. In addition, it isfurther desirable that the check valve exhibit a high degree ofreliability and service life expectancy.

SUMMARY OF THIS INVENTION

An object of this invention is to provide an improved and non-complexcheck valve which provides the above-mentioned desiderata. The checkvalve comprises a housing defining a valve seat thereon and a valvemember movably mounted in the housing to normally engage the seat forblocking fluid flow therepast. A spring means is mounted on the valvemember to bias the valve member into its normal engagement with theseat. A semi-annular retaining means is disposed between a stop means onthe valve member and the spring means and a slot means is formed throughthe stop means and in the valve member to expose an end of the springmeans. The check valve is adapted to be pre-calibrated and attached on amain housing of an integrated valve assembly containing other valvestherein.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects of this invention will become apparent from the followingdescription and accompanying drawings wherein:

FIG. 1 is a longitudinal cross sectional view of a check valve embodyingthis invention;

FIG. 2 is an enlarged perspective view of a spring retaining memberemployed in the check valve;

FIG. 3 is an enlarged perspective view of another spring retainingmember employed in the check valve; and

FIG. 4 is a cross sectional view, taken in the direction of arrowsIV--IV in FIG. 1, illustrating the disposition of a slot employed in thecheck valve to expose an end of the spring employed therein.

DETAILED DESCRIPTION

FIG. 1 illustrates a check valve 10 of the cartridge type comprising anannular housing or case 11 defining a semi-spherical seat 12 therein. Avalve member 13 is reciprocally mounted in the housing to normallyengage the seat in self-aligning relationship to block fluid flow froman inlet 14 to an outlet 15, both defined in a main housing 16. Housing11 is threadably mounted in housing 16 at interengaging screw threads 17to form an integral part thereof and O-ring seals 18 and 19 are mountedbetween housings 11 and 16 to prevent fluid leakage thereby.

Check valve 10 further comprises a stem 20 having a pair of semi-annularretaining members 21 mounted thereon. A stop means, preferably in theform of a radial flange 22, is formed circumferentially on each of theretaining members. As more clearly shown in FIG. 2, a mainsemi-cylindrical body portion 23 of each retaining member extendscircumferentially less than 180° (e.g. 176° ) to form a pair ofdiametrically opposed gaps 24 (one gap shown in FIG. 1). Flanges 22 abutan outboard side of a flange or stop member 25, formed internally onhousing 11. Alternatively, retaining members 21 could be eliminated withspring 31 abutting flange 25 directly.

A second pair of semi-annular retaining members 26 are mounted on stem20 and retained thereon by a stop means comprising an annular flange 27formed on the end of the stem. As shown in FIG. 3, each retaining member26 comprises a semi-cylindrical body portion 28 which also extendscircumferentially approximately 176° to define a pair of diametricallyopposed gaps 29 (FIG. 4). A radial flange 30 is formed on each retainingmember 26 and a spring means 31, preferably a compression coil spring,is mounted between flanges 22 and 30 of axially spaced retaining members21 and 26, respectively.

Referring to FIGS. 1 and 4, a slot means 32 is formed through flange 27and to a limited depth in stem 20 of the valve member to expose an endof spring means 31. The slot means, as shown in FIG. 1, extends axiallypast retaining members 26 and is aligned radially with gaps 29, definedbetween the circumferential ends of the members. An annular cap 33 isthreadably mounted on an end of housing 11 by interengaging screwthreads 34 to fully cover and protect the check valve.

Upon assembly of the check valve in its cartridge form and assumingremoval of cap 33 in FIG. 1, valve member 13 is initially insertedrightwardly in housing 11 to position it against seat 12. Retainingmembers 21 and spring 31 are then mounted on the stem of the valvemember. It should be noted that the spring has an inside diameterslightly greater than the outside diameter of flange 27 to facilitatesuch mounting. A flat tool (not shown) is then inserted in slot means 32to compress spring 31 against flanges 22 of retaining members 21.

Retaining members 26 are then mounted on the stem of the valve member,between flange 27 and spring 31. The tool is then removed from itsengagement with the spring to release it whereby it expands over bodyportions 28 of retaining members 26 to abut flanges 30 thereof to urgethe retaining members into engagement with flange 27. Cap 33 is thenthreadably mounted in place on housing 11 and another O-ring seal 35 maybe disposed between the cap and housing to prevent the egress of fluidthereby.

The check valve is thus pre-calibrated and pre-set in cartridge form.The cartridge is then mounted on main housing 16 at screw threads 34 tobecome an integrated part of a fluid control circuit. Should the checkvalve require servicing, the above procedure may be substantiallyreversed with the tool being inserted in slot 32 to compress spring 31to facilitate removal of retaining members 26 from valve member 13.

What is claimed is:
 1. A valve comprisinga housing defining a valve seatthereon, a valve member movably mounted in said housing and normallyengaging said seat for blocking fluid flow therepast, stop means on saidvalve member, spring means mounted on said valve member for biasing saidvalve member into its normal engagement with said seat, semi-annularretaining means mounted on said valve member and disposed between saidstop means and said spring means for retaining said spring means on saidvalve member, and slot means formed through said stop means and in saidvalve member to expose said spring means whereby insertion of a tool insaid slot means will compress said spring means to facilitateinstallation or removal of said retaining means.
 2. The valve of claim 1further comprising a main housing defining an inlet and an outlettherein and wherein said first-mentioned housing is detachably mountedon said main housing.
 3. The valve of claim 2 wherein said valve memberis reciprocally mounted in said first-mentioned housing to constitute acheck valve adapted to open when the level of fluid pressure in saidinlet exceeds a predetermined maximum.
 4. The valve of claim 1 whereinsaid stop means comprises an annular flange formed integrally on saidvalve member.
 5. The valve of claim 4 wherein said spring meanscomprises a compression coil spring having an inside diameter slightlygreater than an outside diameter of said annular flange.
 6. The valve ofclaim 1 wherein said retaining means comprise a pair of semi-annularretaining members each extending circumferentially less than 180° toform a pair of diametrically opposed gaps between said circumferentialedges of said retaining members, said gaps aligned with said slot means.7. The valve of claim 6 wherein said slot means extends axially in saidvalve member past the axial lengths of said retaining members and saidslot means exposes an end of said spring means.
 8. The valve of claim 6further comprising another pair of semi-annular retaining membersmounted on said valve member in axially spaced relationship relative tosaid first-mentioned pair of retaining members and wherein said springmeans is mounted axially therebetween.
 9. The valve of claim 8 whereineach of said retaining members each comprise a radial flange formedthereon and wherein one end of said spring means engages the radialflanges formed on said first-mentioned pair of retaining members and theother end of said spring means engages the radial flanges formed on saidanother pair of retaining members.
 10. The valve of claim 9 furthercomprising an annular flange formed internally on said housing anddisposed in abutting relationship with the radial flanges formed on saidanother pair of retaining members.
 11. The valve of claim 1 furthercomprising a cap detachably mounted on an end of said housing incovering relationship relative to an end of said valve member havingsaid stop means formed thereon.